A technique has been proposed in which a mode is transitioned to an energy saving mode when data is overwritten to be deleted with reference to a management table in which information on data to be deleted from a disk device is registered, and then access is not performed for a predetermined time in a state where information indicating data to be deleted is absent in the management table.
A technique has been proposed in which a request is registered in an execution waiting task, a storage system returns to the normal mode, and then a logical volume is deleted according to the task including the registered request when a request for deleting of the logical volume is made in an energy saving mode in the storage system.
A technique has been proposed in which a mode of a disk device is transitioned to a power saving mode when the load level is equal to or less than a threshold value, and a situation in which a load is imposed onto a disk device is monitored. Examples of related documents in the related art are Japanese Laid-open Patent Publications Nos. 2005-107856, 2009-238159, and 2002-297320.